This tool lets you extract lyrics and cover art from media files such as mp3 and m4a.
It was born because Apple's Spotlight search did not index lyrics from m4a files and probably still doesn't today. With this you can look up a song by its lyrics if you have it on drive.
Simple, probably buggy, but it works. It requires the mutagen library.
Point is, who on earth still has media files on disk and does not stream these days?